A risk-based approach to improve monitoring and performance of remote waste stabilisation ponds

A cost-effective risk-based system was developed for assessing the performance and potential environmental impact of a large number of geographically dispersed pond systems, where cost and logistical issues prevent direct monitoring. In the process, a range of risk functions were calculated for each site to take into account pond performance, receiving environment, influent quality, surrounding land use and system size. Pond performance was estimated using traditional design equations, including Monte Carlo analysis to account for uncertainty in boundary conditions. The calculation of combined risk functions for all systems enabled the quantitative ranking of systems, which can be used to prioritise limited sampling resources.